The invention relates to a vehicle seat with an adjustment for the seat""s depth. In principle, an adjustment for the depth of seats in vehicles is well-known. Reference is made for example to the DE 197 40 045 A1, DE 196 46 470.6 A1 and DE 196 45 772 A1.
The last mentioned publication discloses a vehicle seat with a seat carrier being composed of two parts, a front part or front transverse part and a U-shaped rear part. The two parts are joined together via two lateral connecting areas. For the depth adjustment of the seat, the lateral connecting areas are both provided with a long hole in which a peg is guided. A device for the mechanical displacement and fixation of the two parts relative to one another is provided.
In principle, this vehicle seat has proved effective. There is however an interest for having its construction further simplified, particularly for doing without the lateral connecting areas and the device for the mechanical displacement and fixation assigned to them. That is where the invention comes to bear.
The object of the invention is to develop the vehicle seat of the type mentioned above in such a way that its construction is simplified and that the installation and the upholstery may be done directly on the complete seat carrier.
The solution of the invention is provided by a vehicle seat having the features of claim 1.
In this vehicle seat, the seat cushion carrier is no longer a single to be handled, mechanically coherent component part. It is now assigned to the seat carrier. The depth adjustment of the seat is done by adjusting the front transverse part relative to the seat carrier, namely to a front area of the seat carrier. The front and rear transverse parts are not directly joined together. They are only connected via the spring area. The rear transverse part in its turn is arranged directly on the seat carrier, more particularly by articulation. Said rear transverse part is essentially designed as an oblong rectangle which is pivotably connected with the hindmost area of the seat carrier by its long lower edge. In the area of its long upper edge it is provided with connecting means for hooking up each single spring of the spring area.
Thus, the operating device for the depth adjustment of the seat may be accommodated in the front part of the seat carrier. From an ergonomic point of view, this is advantageous. A transverse bar located in the central part of the seat as it is provided according to DE 196 45 772 is no longer necessary. Thus, a longer spring excursion is given or less space is needed underneath the seat carrier to achieve the same comfort of springiness.
The rear transverse part is held against the effect of the springs in the spring area in an essentially vertical position by means of an adequate means. To this purpose, the invention suggests arranging a connecting rod between the rear transverse part and each lateral part. Said connecting rod is hinged to the rear transverse part above the lower drag link on one hand. On the other it is slidably guided in a sliding rail provided in each side part. This connecting rod enables the rear transverse part to execute a slewing motion while being further guided.
In an alternative solution, a torsion spring, more particularly a leg spring, is accommodated between the rear transverse part and each lateral part. Said leg spring prestresses the rear transverse part round the lower swivelling axis in such a way that the upper edge of the rear transverse part is pivoted backwards against the action of the spring area. Here too, the position adopted by the rear transverse part is essentially upright thanks this time to the elasticity conferred by the torsion spring. The two just described alternatives may be combined. Other solutions are possible. Instead of a connecting rod, a pressure spring may be used for example on either side of the seat between the rear transverse part and each lateral part. Said pressure spring however acts upon a solid place of the lateral part.
In a preferred embodiment, the adjusting device has an adjustable multiturn actuation arranged on a seat carrier and provided with a rotatable transverse bar cross-tying the two seat carriers and also with one connecting rod each which is linked by one end to the front transverse part. The design of the adjusting device between the front transverse part and the part of the seat carrier located underneath thus results simple.
In the preferred embodiment a long hole, which serves as a longitudinal guiding, is provided in each seat carrier. A slider adapted to the long hole and connected to the front transverse part engages the long hole. The shape of the long hole is discretional. It may for example be straight but it can also be bent. Thanks to this, additionally to the depth adjustment of the seat, the front edge of the seat may also be positioned. In principle and according to the invention, this is altogether possible by designing the shape of the long hole accordingly.
In practice, the distance between the front transverse part and the rear transverse part varies. The change in distance is compensated by the spring area. A padding arranged on the seat carrier and on the seat cushion carrier connected to it, for example a foam part, is designed in such a way that the corresponding change of length may be absorbed in the depth direction of the seat. The same is true for a padding material in which the padding body is wrapped up on the outside.